Melt flow, heat transfer and solidification in a flexible thin slab continuous casting mold with vertical-combined electromagnetic braking

During continuous casting of steel slabs, the application of electromagnetic braking technology (EMBr) provides an effective tool to influence solidification by controlling the pattern of melt flow in the mold. Thus, the quality of the final product can be improved considerably. A new electromagnetic braking (EMBr) method, named vertical-combined electromagnetic braking (VC-EMBr), is proposed to be applied to a flexible thin slab casting (FTSC) mold. To evaluate the beneficial effects of the VC-EMBr, the melt flow, heat transfer, and solidification processes in the FTSC mold are studied by means of numerical simulations. In detail, a Reynolds-averaged Navier-Stokes turbulence model together with an enthalpy-porosity approach was used. The numerical findings are compared with respective simulations using the traditional Ruler-EMBr. The results demonstrate that the application of the VC-EMBr contributes significantly to preventing relative slab defects. In contrast to the Ruler-EMBr, the additional vertical magnetic poles of the VC-EMBr preferentially suppress the direct impact of jet flow on the narrow face of FSTC mold and considerably diminish the level fluctuation near the meniscus region. For instance, by applying a magnetic flux density of 0.3 T, the maximum amplitude of meniscus deflection reduces by about 80%. Moreover, the braking effect of the VC-EMBr effectively improves the homogeneity of temperature distribution in the upper recirculation region and increases the solidified shell thickness along the casting direction. On this basis, the newly proposed VC-EMBr shows a beneficial effect in preventing relative slab defects for FTSC thin slab continuous casting.